A multicenter, randomized, double blind Phase II/III study of the safety, efficacy and dose response of recombinant human relaxin (25 mcg or 10 mcg/kg/day) vs. placebo is proposed in patients with systemic sclerosis with diffuse scleroderma of less than five years duration. The drug will be administered by continuous subcutaneous infusion for 24 weeks. Endpoints will include mesurement of skin thickness and other laboratory tests. The objectives of this study are to replicate the efficacy of relaxin at 25ug/kg/day for 24 weeks in SSc patients with diffuse scleroderma and to support effectiveness of the 25ug/kg/day therapy using a panel of additional variables. Another objective is to evaluate the efficacy and safety of a 10 ug/kg/day dose of relaxin and to continue evaluation of the safety of relaxin.